New track MIRACLE DRUG honours the boy CHRISTOPHER NOLAN's mother, who refused to believe that teaching her paraplegic son was a waste of time.
Singer BONO explains, "He had been deprived of oxygen for two hours when he was born, so he was paraplegic. But his mother believed he could understand what was going on and used to teach him at home.
"Eventually, they discovered a drug that allowed him to move one muscle in his neck. So they attached this unicorn device to his forehead and he learned to type. And out of him came all these poems that he'd been storing up in his head.
"He went off to university and became a genius - all because of a mother's love and a medical breakthrough."
The new album features another emotive track, SOMETIMES YOU CAN'T MAKE IT YOUR OWN, which Bono wrote to perform at his father's funeral last year.